Consolidated Statements of Changes in Shareholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Deferred Benefits for Directors [Member]
Beginning Balance at Dec. 31, 2013	$ 746,595	$ 61,182	$ 244,974	$ 460,351	$ (5,969)	$ (12,734)	$ (1,209)
Beginning Balance, shares at Dec. 31, 2013		29,175,236
Net income	16,421			16,421
Other comprehensive income	3,273					3,273
Comprehensive income	19,694
Common dividends declared ($0.22 per share in Mar 31, 2015 and 2014 respectively	(6,420)			(6,420)
Treasury shares acquired	(19)		49		(68)
Treasury shares acquired, shares		(2,258)
Stock options exercised	976		(176)		1,152
Stock options exercised, shares		37,092
Restricted stock granted			(63)		63
Restricted stock granted, shares		2,040
Stock compensation expense	291		291
Deferred benefits for directors- net			10				(10)
Ending Balance at Mar. 31, 2014	761,117	61,182	245,085	470,352	(4,822)	(9,461)	(1,219)
Ending Balance, shares at Mar. 31, 2014		29,212,110
Beginning Balance at Dec. 31, 2014	788,190	61,182	244,661	504,578	(2,151)	(18,825)	(1,255)
Beginning Balance, shares at Dec. 31, 2014		29,298,188
Net income	13,887			13,887
Other comprehensive income	5,201					5,201
Comprehensive income	19,088
Common dividends declared ($0.22 per share in Mar 31, 2015 and 2014 respectively	(8,843)			(8,843)
Shares issued for acquisition	293,629	19,122	274,507
Shares issued for acquisition, shares		9,178,531
Treasury shares acquired	(1,262)				(1,262)
Treasury shares acquired, shares		(38,237)
Stock options exercised	308		(44)		352
Stock options exercised, shares		11,330
Stock compensation expense	274		274
Deferred benefits for directors- net			1,198				(1,198)
Ending Balance at Mar. 31, 2015	$ 1,091,384	$ 80,304	$ 520,596	$ 509,622	$ (3,061)	$ (13,624)	$ (2,453)
Ending Balance, shares at Mar. 31, 2015		38,449,812